Water pump for vehicle

ABSTRACT

A water pump for a vehicle may include a pulley provided with a through bore formed at a middle portion thereof, a clutch compartment being formed at a rear surface along a circumference of the through bore, a brake pad mounted at an interior surface of the clutch compartment of the pulley, a clutch disk disposed in the clutch compartment of the pulley corresponding to the brake pad, a hub coupled to the through bore of the pulley through a pulley bearing, and connected to the clutch disk through a plurality of spring pins mounted at an external circumferential portion thereof, a return spring mounted at the spring pin between the clutch disk and the hub, and applying elastic force to the clutch disk, a field coil disposed in the clutch compartment of the pulley and wrapped a coil case and a cover corresponding to a rear surface of the clutch disk, and a main shaft rotatably mounted to a pump body through a pump bearing, and provided with one end portion connected to a middle portion of the hub and the other end portion connected to an impeller by interposing a sealing unit therebetween, wherein the clutch disk comprises a plurality of first ring members piled up coaxially, each first ring member has a different diameter, and first molding portions which are operated as nonmagnetic adhesives are formed between the first ring members.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Korean Patent Application Number 10-2009-0120065 filed in the Korean Intellectual Property Office on Dec. 4, 2009, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a water pump for a vehicle. More particularly, the present invention relates to a water pump for a vehicle provided with an electric clutch.

2. Description of the Related Art

Currently, vehicle manufactures tries to achieve two objectives (that is, improving fuel consumption and reducing emission). Particularly, catalyst amount loaded in an exhaust system is increased or capacity of an EGR cooler is increased in order to meet emission regulations although cost and weight are greatly increased.

Generally, a coolant is forcibly circulates in a vehicle. For this purpose, a coolant path is formed in a cylinder and a cylinder head of an engine, and the coolant is forcibly supplied in the coolant path by an operation of a water pump. Thereby, temperature of the engine is stably maintained.

The water pump for supplying the coolant to the coolant path is operated by torque transmitted through a belt, and circulates the coolant in a sequence of “radiator→cylinder→cylinder head→radiator”. Thereby, the water pump prevent the engine from being overheated and degraded.

An impeller having about six blades is rotated by the torque transmitted from the engine to the water pump through the belt and pumps the coolant to the cylinder. The rotation speed of the impeller is set according to a pulley ratio, but is about 1.2-1.6 times faster than that of a crankshaft.

The water pump is always operated by the torque transmitted through the belt when the engine operates. Therefore, the water pump always operates and circulates the coolant regardless of warming-up condition or cooling condition of the engine when the engine operates.

Therefore, fuel consumption and exhaust gas may be stabilized in a state that warming-up of the engine is completed, but the warming-up of the engine may be delayed by circulation of the coolant in a state that the engine is started when temperature of the engine is cool. Therefore, friction resistance at a cooled part and abrasion thereof increase.

In addition, since combustion efficiency is deteriorated by the engine of low temperature, fuel consumption may increase, temperature rise of the exhaust gas may be delayed, and activation time of the catalyst may be delayed. Therefore, the exhaust gas having a large amount of noxious materials may be exhausted and the emission may be unstable.

Since continuous operation of the water pump is operated as a load to the crankshaft, output efficiency of the engine and fuel consumption may be deteriorated.

These are because the water pump is always connected to the crankshaft by the belt.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a water pump for a vehicle having advantages of selectively pumping coolant as a consequence that the water pump is provided with an electric clutch and an operation of the electric clutch is controlled according to a driving condition of an engine and a coolant temperature condition.

A water pump for a vehicle according to the present invention may include a pulley provided with a through bore formed at a middle portion thereof, a clutch compartment being formed at a rear surface along a circumference of the through bore, a brake pad mounted at an interior surface of the clutch compartment of the pulley, a clutch disk disposed in the clutch compartment of the pulley corresponding to the brake pad, a hub coupled to the through bore of the pulley through a pulley bearing, and connected to the clutch disk through a plurality of spring pins mounted at an external circumferential portion thereof, a return spring mounted at the spring pin between the clutch disk and the hub, and applying elastic force to the clutch disk, a field coil disposed in the clutch compartment of the pulley and wrapped a coil case and a cover corresponding to a rear surface of the clutch disk, and a main shaft rotatably mounted to a pump body through a pump bearing, and provided with one end portion connected to a middle portion of the hub and the other end portion connected to an impeller by interposing a sealing unit therebetween, wherein the clutch disk comprises a plurality of first ring members piled up coaxially, each first ring member has a different diameter, and first molding portions which are operated as nonmagnetic adhesives are formed between the first ring members.

The first ring members may be integrally formed with each other by the first molding portions and the first molding portions may be operated as slots of the clutch disk.

The coil case may include a first case surface formed at an internal circumference thereof, a second case surface formed at an external circumference thereof, and a third case surface connecting an end portion of the first case surface to an end portion of the second case surface.

The third case surface may include a plurality of second ring members piled up coaxially, and each second ring member may have a different diameter. Second molding portions which are operated as nonmagnetic adhesives may be formed between the second ring members and between the second ring members and the first and second case surfaces.

The second ring members and the first and the second case surfaces may be formed integrally with each other through the second molding portions and the second molding portions may be operated as slots of the coil case.

The first ring members may be disposed corresponding to the second molding portions, and the second ring members may be disposed corresponding to the first molding portions.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of an exemplary water pump for a vehicle according to the present invention.

FIG. 2 is a cross-sectional view of an exemplary water pump for a vehicle according to the present invention.

FIG. 3 is a perspective view of an exemplary clutch disk applied to a water pump for a vehicle according to the present invention.

FIG. 4 is a cross-sectional view of the clutch disk shown in FIG. 3.

FIG. 5 is a perspective view of an exemplary coil case applied to a water pump for a vehicle according to the present invention.

FIG. 6 is a cross-sectional view of the coil case shown in FIG. 5.

FIG. 7 is a schematic diagram showing an operation of an exemplary water pump for a vehicle according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

In addition, size and thickness of components shown in the drawings may be differ from real size and real thickness of the components for better comprehension and ease of description.

Thickness of the components may be enlarged at many parts in the drawings for clear expression.

FIG. 1 is an exploded perspective view of a water pump for a vehicle according to the present invention, and FIG. 2 is a cross-sectional view of a water pump for a vehicle according to the present invention.

Referring to the drawings, a water pump 100 for a vehicle according to the present invention forcibly supplies a coolant to a coolant path by torque of an engine transmitted through a belt and maintains temperature of the engine stably.

The water pump 100 for a vehicle includes a pump body 110, a pulley 130 connected to a crankshaft of the engine, rotatably coupled to one side of the pump body 110, receiving the torque of the engine through the crankshaft, and an impeller 150 rotatably mounted to the pump body 110 so as to be rotated according to a rotation of the pulley 130 and pumping the coolant.

Therefore, when the engine is started, the pulley 130 is rotated by the torque transmitted from the crankshaft through the belt. Therefore, the impeller 150 rotates and pumps the coolant.

Thereby, the coolant is supplied to the coolant path formed in a cylinder (not shown) by the torque of the impeller 150, and the temperature of the engine is stably maintained by the coolant.

According to the present exemplary embodiment, the water pump 100 for a vehicle is provided with an electric clutch, and controls an operation of the electric clutch according to a driving condition of the engine, a coolant temperature, and a driver's intention such that the coolant is pumped selectively.

For this purpose, the water pump 100 for a vehicle according to the present invention includes a brake pad 210, a clutch disk 220, a hub 230, a return spring 240, a field coil 260, and a main shaft 270 as well as the pump body 110, the pulley 130, and the impeller 150 as described above.

The pump body 110 is provided with the pulley 130 at one side and the impeller 150 at the other side. The pulley 130 is selectively connected to one end portion of the main shaft 270 and is rotated, and the impeller 150 is connected to the other end portion of the main shaft 270 and is rotated.

The pulley 130 for receiving the toque from the crankshaft (not shown in the drawings) of the engine through the belt is provided with a through bore or through bore 131 formed at a middle portion thereof. A pulley bearing 133 is mounted at the through bore 131.

A clutch compartment or clutch space 135 is formed at a rear surface of the pulley 130 along the through bore or through bore 131, and a mounting groove 137 for mounting the brake pad 210 is formed at an interior surface of the clutch compartment 135 along the through bore 131.

The brake pad 210 has a ring shape and is made of steel materials. The brake pad 210 is mounted at a rear surface of the pulley 130. That is, the brake pad 210 is inserted in and bonded to the mounting groove 137 formed at the interior surface of the clutch compartment 135.

The clutch disk 220 is disposed in the clutch compartment 135 of the pulley 130 corresponding to the brake pad 210, and has a disk shape. The clutch disk 220 is able to be closely contacted to the brake pad 210.

The torque transmitted to the pulley 130 can be selectively transmitted to the hub 230 according to the selective connection of the clutch disk 220 and the brake pad 210.

According to the present exemplary embodiment, the clutch disk 220 includes a plurality of first ring members 221 piled up coaxially as shown in FIG. 3 and FIG. 4. Each first ring member 221 has a different diameter. First molding portions 223 are formed between the first ring members 221.

The first ring members 221 are connected to each other by the first molding portions 223, not by a bridge. Each first ring member 221 has the same thickness and is coaxially disposed with an even space. Since the space between the first ring portions 221 is filled with the first molding portions 223, the first ring portions 221 is integrally formed by the first molding portions 223. One will appreciate that the first ring portions are securely affixed to one another by the first molding portions. One will also appreciate that the first molding portions may be molded in situ between the first ring portions.

That is, the first ring members 221 with different diameters are disposed coaxially so as to form the even space therebetween, and the first molding portions 223 which are operated as nonmagnetic adhesives are molded to the space between the first ring members 221. Since the first ring members 221 are bonded to each other by the first molding portions 223, the first ring members 221 s are integrally formed with each other by the first molding portions 223. Again, one will appreciate that the first ring portions are securely affixed to one another by the first molding portions. One will also appreciate that the first molding portions may be molded in situ between the first ring portions.

Since the first molding portions 223 are formed between the first ring members 221, the first molding portions 223 are operated as slots of the clutch disk 220 in which the first ring members 221 are inserted according to the present exemplary embodiment.

The hub 230 is rotatably coupled to the through bore 131 of the pulley 130 through the pulley bearing 133, and is connected to the clutch disk 220 through a plurality of spring pins 231 (see FIG. 1).

The spring pins 231 connect an external circumferential portion of the hub 230 to an internal circumferential portion of the clutch disk 220. For this purpose, the spring pin 231 is connectedly mounted in a first mounting hole 233 formed at external circumferential portion of the hub 230 and a second mounting hole 224 formed at the internal circumferential portion of the clutch disk 220.

That is, each spring pin 231 penetrates the first and the second mounting holes 233 and 224, one end portion of the spring pin 231 is supported by the external circumferential portion of the hub 230, and the other end portion of the spring pin 231 is supported by the internal circumferential portion of the clutch disk 220.

The return spring 240 may be a coil spring. The return spring 240 is mounted at the spring pin 231 between the clutch disk 220 and the hub 230, and applies elastic force to the clutch disk 220.

The field coil 260 receives electric power according to a control signal of the exterior and generates magnetic force. The field coil 260 is mounted in the clutch compartment 135 of the pulley 130 corresponding to the rear surface of the clutch disk 220.

The field coil 260 is mounted in the coil case 261 magnetized by the magnetic force. Since the coil case 261 is covered by a cover 263, the field coil 260 is disposed in the coil case 261.

According to the present exemplary embodiment, the coil case 261 for receiving the field coil 260 includes a first case surface 265 a formed at an internal circumference thereof, a second case surface 265 b formed at an external circumference thereof, and a third case surface 265 c connecting an end portion of the first case surface 265 a to an end portion of the second case surface 265 b, as shown in FIG. 5 and FIG. 6.

The coil case 261 is formed of a hole corresponding to the clutch disk 220, and external circumference of the hole is the first case surface 265 a. In addition, a surface corresponding to the rear surface of the clutch disk 220 is the third case surface 265 c.

The third case surface 265 c includes a plurality of second ring members 267 piled up coaxially, and each second ring member 267 has a different diameter. Second molding portions 268 which are operated as nonmagnetic adhesives are formed between the second ring members 267 and between the second ring members 267 and the first and second case surfaces 265 a and 265 b.

The second ring members 267 are connected to each other by the second molding portions 268, not by a bridge. Each second ring member 267 has the same thickness and is coaxially disposed with en even space. Since the space between the second ring members 267 is filled with the second molding portions 268, the second ring members 267 and the first and second case surfaces 265 a and 265 b are integrally formed with each other by the second molding portions 268. One will appreciate that the first and second case surfaces are securely affixed to one another by the second molding portions. One will also appreciate that the second molding portions may be molded in situ between the case surfaces.

That is, the second ring members 267 with different diameters are disposed coaxially so as to form the even space therebetween, and the second molding portions 268 which are operated as the nonmagnetic adhesives are molded to the space between the second ring members 267. Therefore, the second ring members 267 are integrally formed with each other by the second molding portions 268, and form the third case surface 265C. One will appreciate that the second ring members are securely affixed to one another by the second molding portions. One will also appreciate that the second molding portions may be molded in situ between the second ring members.

After that, the third case surface 265 c is disposed between the first and second case surfaces 265 a and 265 b apart from them 265 a and 265 b, and the second molding portions 268 are molded to spaces formed between the third case surface 265 c and the first case surface 265 a, and between the third case surface 265 c and the second case surface 265 b.

Since the second molding portions 268 are formed between the second ring members 267 of the third case surface 265 c and between the third case surface 265 c and the first and second case surfaces 265 a and 265 b, the second molding portions 268 are operated as slots of the third case surface 265 c in which the second ring members 267 are inserted according to the present exemplary embodiment.

The main shaft 270 is rotatably mounted to the pump body 110 through a pump bearing 271. One end of the main shaft 270 is connected to a center of the hub 230, and the other end of the main shaft 270 is connected to the impeller 150 by interposing a sealing unit 273 for sealing the pump body 110 therebetween.

According to the water pump 100 for a vehicle, the clutch disk 220 is closely contacted to the brake pad 210 by the elastic force of the return spring 240 in a normal state that the electric power is not applied to the field coil 260 as shown in FIG. 2.

At this time, the clutch disk 220 is connected to the hub 230 through the spring pin 231 and is closely contacted to the brake pad 210. If the torque of the engine is transmitted to the pulley 130 through the belt, the torque of the engine is delivered to the main shaft 270 through the clutch disk 220 and the hub 230 according to the rotation of the pulley 130. Therefore, the main shaft 270 rotates, and the impeller 150 is rotated by the rotation of the main shaft 270 and pumps the coolant.

The coolant is pumped when the engine speed is faster than a predetermined rotation speed (that is, the engine operates at a high speed) or when the engine speed is smaller than the predetermined rotation speed but the temperature of the coolant is higher than or equal to a predetermined temperature.

In addition, in order to warm up a cabin of the vehicle quickly, the coolant is pumped when a heater switch is turned on regardless the engine speed and the temperature of the coolant.

However, if the above described conditions are not satisfied, that is, the engine operates at a low speed, the temperature of the coolant is lower than the predetermined temperature, or the heater switch is turned off, the field coil 260 receives the electric power according to the control signal and generates the magnetic force.

At this time, the coil case 261 is magnetized by the magnetic force generated at the field coil 260, and the coil case 261 pulls the clutch disk 220 by the magnetic force, as shown in FIG. 7.

Then, the clutch disk 220 overcomes the elastic force of the return spring 240 and moves toward the coil case 261. Thereby, the clutch disk 200 is detached from the brake pad 210.

If the clutch disk 220 is detached from the brake pad 210, the connection of the clutch disk 220 and the brake pad 210 is cut off. Therefore, the torque is not transmitted to the main shaft 270 through the hub 230, the pulley 130 idles. Therefore, the impeller 150 does not rotate, and the coolant is not pumped.

As described above, as a consequence that the clutch is electrically operated by the control signal according to the driving condition of the engine and the temperature of the coolant, the torque of the pulley 130 is transmitted to the impeller 150 or not according to the present invention. The pumping of the coolant is selectively done by the impeller 150.

Since stable emission is secured though loading amount of the catalyst purifying the exhaust gas does not increase, cost may be reduced. Since additional components are not added to an exhaust system, weight of the vehicle may be reduced and fuel mileage may be improved.

Since circulation of the coolant is prevented when cold-starting of the engine, the temperature of engine oil may be quickly raised. Therefore, friction may be reduced, abrasion of each driving component may be minimized, and durability may be improved.

According to the present exemplary embodiment, the circulation of the coolant is actively controlled at an initial starting of the engine. Therefore, activation time of the engine and the catalyst may be shortened, fuel mileage may be enhanced as a consequence of a stable combustion, and the emission may be stabilized.

Meanwhile, if the electric power is applied to the field coil 260 and the torque is not transmitted to the main shaft 270, a magnetic field generated at the field coil 260 has an orientation by the coil case 261 and forms a magnetic flux flowing along the coil case 261 according to the present invention.

Such a magnetic flux flows through the first case surface 265 a or the second case surface 265 b of the coil case 261, and forms a first pole toward the first ring member 221 of the clutch disk 220.

In addition, the magnetic flux delivered to the first ring member 221 of the clutch disk 220 does not flow by the first molding portion 223 of the clutch disk 220, and forms a second pole toward the second ring member 267 of the coil case 261.

In addition, the magnetic flux delivered from the first ring member 221 of the clutch disk 220 to the second ring member 267 of the coil case 261 does not flow by the second molding portion 268 of the coil case 261, and forms a third pole toward the first ring member 221 of the clutch disk 220.

Since the clutch disk 220 is formed by molding the first molding portions 223 of the nonmagnetic adhesives between the first ring members 221 and the coil case 261 is formed by molding the second molding portions 268 of the nonmagnetic adhesives between the second ring members 267, a plurality of poles are generated at the first ring members 221 of the clutch disk 220 and the second ring members 267 of the coil case 261 according to the present exemplary embodiment.

Since the first molding portions 223 of the clutch disk 220 and the second molding portions 268 of the coil case 261 are crossed and are operated as the slots of the first and the second ring members 221 and 267, the magnetic flux does not flow by the molding portions 223 and 268 and is applied alternately to the first and second ring members 221 and 267. Therefore, a plurality of poles is formed.

Since the magnetic force is proportional to the numbers of the poles generated at the clutch disk 220 and the coil case 261, stronger magnetic force is generated by the same magnetic filed. Power delivery efficiency through the clutch disk 220 may be improved.

Since a target magnetic force is generated with a weaker magnetic field by generating a plurality of poles according to the present exemplary embodiment, the numbers of winding the field coil 260 and electricity consumption may be reduced, and weight of the field coil 260 and the pump 100 may be reduced.

As described above, as a consequence that the clutch is electrically operated by the control signal according to the driving condition of the engine and the temperature of the coolant, the torque of the pulley is transmitted to the impeller or not according to the present invention. The pumping of the coolant is selectively done by the impeller.

Since stable emission is secured though loading amount of the catalyst purifying the exhaust gas does not increase, cost may be reduced. Since additional components are not added to an exhaust system, weight of the vehicle may be reduced and fuel mileage may be improved.

Since circulation of the coolant is prevented when cold-starting of the engine, the temperature of engine oil may be quickly raised. Therefore, friction may be reduced, abrasion of each driving component may be minimized, and durability may be improved.

According to the present exemplary embodiment, the circulation of the coolant is actively controlled at an initial starting of the engine. Therefore, activation time of the engine and the catalyst may be shortened, fuel mileage may be enhanced as a consequence of a stable combustion, and the emission may be stabilized.

Since the first molding portions of the clutch disk and the second molding portions of the coil case are crossed and are operated as the slots of the first and the second ring members, the magnetic flux does not flow by the molding portions and is applied alternately to the first and second ring members. Therefore, a plurality of poles may be formed.

Since the magnetic force is proportional to the numbers of the poles generated at the clutch disk and the coil case, stronger magnetic force is generated by the same magnetic filed. Power delivery efficiency through the clutch disk may be improved.

Since a target magnetic force is generated with a weaker magnetic field by generating a plurality of poles according to the present exemplary embodiment, the numbers of winding the field coil and electricity consumption may be reduced, and weight of the field coil and the pump may be reduced.

For convenience in explanation and accurate definition in the appended claims, the terms “upper” or “lower”, “front” or “rear”, “inside” or “outside”, and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

1. A water pump for a vehicle comprising: a pulley having a through bore formed at a middle portion thereof, and a clutch compartment formed at a rear surface thereof along a circumference of a through bore; a brake pad mounted on an interior surface of the clutch compartment of the pulley; a clutch disk disposed in the clutch compartment of the pulley corresponding to the brake pad; a hub rotatably coupled to the pulley about the through bore through a pulley bearing, the hub rotatably affixed to the clutch disk through a plurality of spring pins mounted at an external circumferential portion thereof; a return spring mounted on at least one of said spring pins between the clutch disk and the hub, wherein the return spring applies elastic force to the clutch disk; a field coil disposed in the clutch compartment of the pulley and enclosed by a coil case and a cover, the field coil corresponding to a rear surface of the clutch disk; a main shaft rotatably mounted to a pump body through a pump bearing, the main shaft having a first end portion connected to a middle portion of the hub and a second end portion connected to an impeller; and a sealing unit mounted on the main shaft between said first and second end portions, wherein the clutch disk comprises a plurality of first ring members arranged coaxially, each first ring member has a different diameter, and a plurality of first molding portions which provide nonmagnetic adhesives interconnecting adjacent first ring members.
 2. The water pump of claim 1, wherein the first ring members are integral with each other by respective first molding portions and the first molding portions serve as slots of the clutch disk.
 3. The water pump of claim 1, wherein the coil case comprises a first case surface formed at an internal circumference thereof, a second case surface formed at an external circumference thereof, and a third case surface connecting an end portion of the first case surface to an end portion of the second case surface, wherein the third case surface includes a plurality of second ring members piled up coaxially, and each second ring member has a different diameter, and wherein second molding portions which serve as nonmagnetic adhesives between the second ring members and between the second ring members and the first and second case surfaces.
 4. The water pump of claim 3, wherein the second ring members and the first and the second case surfaces are integral with each other through the second molding portions and the second molding portions are operated as slots of the coil case.
 5. The water pump of claim 3, wherein the first ring members are disposed corresponding to the second molding portions, and the second ring members are disposed corresponding to the first molding portions. 